title: Polarization control of high order harmonics in the EUV photon energy range.
abstract: We report the generation of circularly polarized high order harmonics in the extreme ultraviolet range (18-27 nm) from a linearly polarized infrared laser (40 fs, 0.25 TW) focused into a neon filled gas cell. To circularly polarize the initially linearly polarized harmonics we have implemented a four-reflector phase-shifter. Fully circularly polarized radiation has been obtained with an efficiency of a few percents, thus being significantly more efficient than currently demonstrated direct generation of elliptically polarized harmonics. This demonstration opens up new experimental capabilities based on high order harmonics, for example, in biology and materials science. The inherent femtosecond time resolution of high order harmonic generating table top laser sources renders these an ideal tool for the investigation of ultrafast magnetization dynamics now that the magnetic circular dichroism at the absorption M-edges of transition metals can be exploited.
authors.affiliation: Laboratoire d'Optique Appliquée, ENSTA ParisTech-CNRS-cole polytechnique, Chemin de la Hunire, Palaiseau, France. boris.vodungbo@ensta-paristech.fr
authors.forename: Boris
authors.initials: B
authors.lastname: Vodungbo
authors.forename: Anna
authors.initials: A
authors.lastname: Barszczak Sardinha
authors.forename: Julien
authors.initials: J
authors.lastname: Gautier
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lambert
authors.forename: Constance
authors.initials: C
authors.lastname: Valentin
authors.forename: Magali
authors.initials: M
authors.lastname: Lozano
authors.forename: Grégory
authors.initials: G
authors.lastname: Iaquaniello
authors.forename: Franck
authors.initials: F
authors.lastname: Delmotte
authors.forename: Stéphane
authors.initials: S
authors.lastname: Sebban
authors.forename: Jan
authors.initials: J
authors.lastname: Lüning
authors.forename: Philippe
authors.initials: P
authors.lastname: Zeitoun
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D007909:Lenses; D017785:Photons; D012031:Refractometry / Q000295:instrumentation*; D014466:Ultraviolet Rays